The Beaufort Scale devised by Admiral Sir Francis Beaufort to categorize various wind speeds. Home
Beaufort Scale.
The Beaufort scale is used to quantify wind strength, it divides wind speed into twelve categories. The scale was devised by, and named after Admiral Sir Francis Beaufort in 1805, who was a hydrographer to the British Navy. It received international recognition in 1874.
| Beaufort Scale |
Wind Speed (knots) |
Description | Sea state |
| 0 | Less than 1. |
Calm. | Water surface like a mirror. |
| 1 | 1-3 | Light air. | Small ripples, with no crests. |
| 2 | 4-6 | Light breeze. | Small wavelets, crests on the point of breaking. |
| 3 | 7-10 | Gentle breeze. | Large wavelets, crests beginning to break. |
| 4 | 11-16 | Moderate breeze. | Small waves becoming larger, with frequent white crests. |
| 5 | 17-21 | Fresh breeze. | Moderate waves, with many white crests and some spray. |
| 6 | 22-27 | Strong breeze. | Large waves, white foam crests and spray. |
| 7 | 28-33 | Near gale. | Sea heaps up, breaking waves with white foam beginning to blow in streaks. |
| 8 | 34-40 | Gale. | Moderately high waves, with breaking crests and foam streaks. |
| 9 | 41-47 | Severe gale. | High waves, with crests tumbling and spray affecting visibility. |
| 10 | 48-55 | Storm. | Very high waves, with long breaking crests and poor visibility. |
| 11 | 56-63 | Violent storm. | Exceptionally high waves, with the sea frothing and foaming. Very poor visibility. |
| 12 | 64 plus | Hurricane. | Huge waves, with the sea completely white and the air filled with foam and spray. Extremely poor visibility. |